protective layers or coating compositions or methods of applying them; these are classified in the appropriate places, e.g. B05, B44, C09D, C23C.

mechanical devices or constructional features of particular articles for inhibiting incrustation; these are classified in the appropriate places, e.g. in pipes or pipe fittings F16L 58/00.

articles characterised by being made of materials selected for their properties of resistance to corrosion or incrustation; these are classified in the appropriate places, e.g. turbine blades F01D 5/28.

Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent (adding inhibitors to mineral oil, fuels, or lubricants C10; adding inhibitors to pickling solutions C23G) [2013‑01]

C23F 11/02

.

in air or gases by adding vapour phase inhibitors [2013‑01]

C23F 11/04

.

in markedly acid liquids [2013‑01]

C23F 11/06

.

in markedly alkaline liquids [2013‑01]

C23F 11/08

.

in other liquids [2013‑01]

C23F 11/10

. .

using organic inhibitors [2013‑01]

NOTE

-

A compound is classified in the last appropriate place.

Esters or anhydrides of organic acids are classified as the relevant acid unless otherwise indicated. Salts of a compound with an inorganic compound are classified as that compound unless specifically provided for.

Multi-step processes for surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by subclass C21D or C22F or class C25(C23C 28/00 takes precedence) [2013‑01]

C23F 2201/00

Type of materials to be protected by cathodic protection [2013‑01]

C23F 2201/02

.

Concrete, e.g. reinforced [2013‑01]

C23F 2213/00

Aspects of inhibiting corrosion of metals by anodic or cathodic protection [2013‑01]

C23F 2213/10

.

Controlling or regulating parameters [2013‑01]

C23F 2213/11

. .

for structures subject to stray currents [2013‑01]

C23F 2213/20

.

Constructional parts or assemblies of the anodic or cathodic protection apparatus [2013‑01]

C23F 2213/21

. .

combining at least two types of anodic or cathodic protection [2013‑01]